This suffix is frequently used to create the adjective form of a noun, especially in the form -ëa for nouns ending in -ë. This function dates back to CE. ✶-ā.
Quenya
-ina
general 'passive' participle
-ina
suffix. adjective suffix; passive participle
ina
(stronger) the
-a
suffix. adjectival suffix
-ina ending for what Tolkien called "general 'passive' participle" (VT43:15); compare nótina "counted", rácina "broken", hastaina "marred" (q.v.). The stem-vowel is usually lengthened when the ending is added to the stem of a primary verb (as in the two first examples above), though the lengthening fails to occur (or is not denoted) in carina as the passive participle of car- "make, do" (VT43:15).